Projection type display devices (i.e. projectors) can display enlarged images on a projection screen, and are therefore often used in presentations. In a typical presentation, a plurality of presentation sheets (also called “slides”) are sequentially displayed in pages. This process is executed according to a scenario file representing pagewise sequential display of images. Image files used in accordance with scenario files and index files are prepared in advance by the user, and supplied to a projector.
However, in a projector, pagewise sequential display of images is sometimes difficult because it is relatively hard to create or describe scenario files using predetermined commands or prepare image files representing images for display according to a scenario file, in a format suitable for a projector.
Also, when reproducing an image file or a data file, the projector requires a storage device having capacity capable of storing the image file, and there is a need for a technique for reducing the required capacity of a storage device of a projector.